受端混联型LCC-VSC直流输电线路快速后备保护  

Fast Back-up Protection Scheme of Receiving-End Hybrid LCC-VSC DC Transmission Lines

作　　者：武传健 张大海[1] Wu Chuanjian;Zhang Dahai(School of Electrical Engineering Beijing Jiaotong University,Beijing 100044 China)

机构地区：[1]北京交通大学电气工程学院,北京100044

出　　处：《电工技术学报》2021年第S02期541-553,共13页Transactions of China Electrotechnical Society

基　　金：国家电网有限公司科技资助项目(5100-201955018A-0-0-00)。

摘　　要：混联多端直流输电技术集中了电网换相换流器(LCC)和电压源型换流器(VSC)两种换流器技术的优势,具有广阔的发展前景,多端混联导致其输电线路故障特性区别于传统单一直流系统。该文对LCC-VSC混合多端直流输电线路故障特性进行分析,发现输电线路故障时存在两侧电流不平衡、LCC支路和VSC支路对后备保护时间要求不同的问题,传统的微分欠电压保护和电流差动保护难以作为整条输电线路的后备保护。针对此问题,提出基于单端电气量的双加速反时限过电流保护方案作为输电线路行波保护的快速后备保护,利用两端不同整定值的方案解决两侧电流不平衡问题;利用反时限特性同时配合两条支路的主保护,并且其受分布式电容和过渡电阻的影响较小。最后通过仿真实验证明了该方案的有效性。Hybrid multi-terminal DC transmission technology combines the advantages of the two converter technologies and has broad development prospects.The fault characteristics of the transmission line of the multi-terminal hybrid system are different from the traditional single DC system.The fault characteristics of the hybrid multi-terminal DC transmission line are analyzed in this paper.it is found that there are current imbalances on both sides when the transmission line faults,and the backup protection time requirements of the LCC branch and the VSC branch are different.The traditional differential undervoltage protection and current differential protection is difficult to serve as backup protection for the entire transmission line.In order to solve the problem,a dual-acceleration inverse time overcurrent protection scheme based on single-end electrical quantities is proposed as a fast backup protection for the transmission line traveling wave protection.The scheme of different setting values at both ends to solve the problem of current imbalance on both sides was used in this paper.The inverse time limit feature can be used to cooperate with the main protection of two branches at the same time.Therefore,the protection scheme is less affected by distributed capacitance and transition resistance.Finally,simulation results prove the effectiveness of the scheme.

关 键 词：混合多端直流输电 线路保护 反时限 加速因子 方向判据 

分 类 号：TM773[电气工程—电力系统及自动化]